Case selector



Dec. 21, 1965 E. K. HYYPOLAINEN 3,225,175

CASE SELECTOR Filed July 18. 1960 6 Sheets-Sheet 1 FIGZ. k

IN VEN TOR. ERKKI K. HYYPOZHZZVEN ATTORNEY Dec. 21, 1965 E. K.HYYPOLAINEN CASE SELECTOR Filed July 18. 1960 FIGB.

6 Sheets-Sheet 2 PICK u HEADS L 0 G 6 V MM oRY COMPARATOR OUTPUT 6A TECLO CK r G U D E READOUT MEMORY COMMAND OUTPUT OUTPUT D INVENTOR.

OUTPUT EPRKI K.HYYPOLAINEN 5 ATTORNEY Dec. 21, 1965 Filed July 18, 19606 Sheets-Sheet 3 CLOCK SET 5% GATE COUNTER r r v OUTPUT COMPARATORMEMORY GUIDE RCADOUT /COMMAND CLOCK RESET RESET 'AND- F V GATE COUNTER YI com:

SELECTOR SWITCHES MEMORY GUIDE OUTPUT COMPARATOR FIGS.

READOUT COMMAND IN VEN TOR.

RKKIKZ HYYPOLAINEN ATTORNEY Dec. 21, 1965 E. K. HYYPOLAINEN CASESELECTOR 6 Sheets-Sheet 4 Filed July 18. 1960 KIDQLAQQ ATTORNEY INVENTOR ERKKI (.HYYPOLAINH] -MCA&.

WZZQIQ XU OQU 1965 E. K. HYYPOLAINEN 3,225,175

CASE SELECTOR Filed July 18, 1960 6 Sheets-Sheet 5 our/ un Z' I TP/25557 OUTPUT OUT/ K7 (ISL,

NEGATIVE PULSE PULSE OUTPUT OUTPUT mpur '--H| INVENTOR.

E'RKKI ICHYYPOLAINEN a g w c,' QM

ATTORNEY 1965 E. K. HYYPOLAINEN 3, 7

CASE SELECTOR Filed July 18. 1960 6 Sheets-Sheet 6 IN VENTOR ERKKI K.HYYPOLA INEN ATTORNEY United States Patent Ofiice 3,225,175- PatentedDec. 21, 1965 3,225,175 CASE SELECTOR Erkki K. Hyypolainen, Chester,Pa., assignor to Scott Paper Company, Chester, Pa., a corporation ofPennsylvania Filed July 18, 1960, Ser. No. 43,567 8 Claims. (Cl.23561.7)

The present invention relates to selector or sorting apparatus generallyused in connection with conveyor systems. Thus the present invention hasparticular application in the field of warehousing where a great numberof generally similar but specifically different items, such as cartons,cases or boxes, pass along a conveyor. The case selector of the presentinvention is utilized to actuate sorting devices operating inconjunction with the conveyor for moving the items, selectively, fromthe conveyor to destination points such as box cars, trucks or selectedstorage places.

More specifically, the case selector of the present invention utilizesor detects a group of marks printed on the sides of each case or cartonand, if the carton carries marks printed in an appropriate array,through an electronic selector generates a pulse which actuates a tripor similar ejection device for removing that carton from the conveyor.Thus the device of the present invention is referred to as a caseselector.

Broadly speaking, the case selector includes two elements, aphotoelectric pickup and a case selector logic cabinet. The pickup isfastened at the side of the conveyor that carries the cartons at a usualspeed of at least about 100 ft./min. The case selector logic cabinet canbe located as far away as several thousand feet from the photoelectricpickup.

The pickup contains only two photo cells or eyes which are arrangedclose together. Therefore, the area of even illumination which isrequired is very small, being only a few inches square. The light sourceis a simple 30 watt spotlight, operating at lower than normal voltagewith a life expectancy of several thousand hours and the light source isresiliently mounted so as to damp out conveyor vibrations. A spare lightsource is provided which automatically takes over if the first lampburns out. The pickup box is dusttight and has a flat glass window whichis easy to clean and will not very easily collect dust.

The two photoelectric pickup heads, one above another, slightlystaggered, control four different operations:

(1) Receive the code signals, caused by the changing intensity of lightreflected from a moving printed pattern,

(2) Direct the code signals to proper storage or memory units,

(3) Initiate the readout and (4) Reset or clear the complete system.

In the past, photoelectric pickup heads have been utilized in caseselectors, but generally speaking there have been more than two photocells or eyes required for each selector. Because of the construction ofsuch prior devices, which may be best described as parallel input, D.C.coupled (or A.C. coupled) units, various unsatisfactory results areattained. Some ofithe principal disadvantages of such prior devices, arethe sensitivity to (a) changes in light intensity, (b) the condition ofthe surface of the object being scanned and (c) similar problemsinvolving the optics of the system. In addition, such selectors haverequired so many components, particularly the photo electric cells, thatany variation in the construction or condition of the device tended tomultiply the errors (being particularly true with regard to illuminationand optical effects) so that it has been difficult to provide efiiciencyin the operation of the device.

Of particular concern has been the requirement that a large number ofphoto electric cells be used. For example, if the number of cartons orcases to be detected is 2 or 256, a parallel input selector systemrequires at least 8+2 or 10 separate photoelectric pickup heads andinput channels.

The selector of the present invention is a serial input photoelectricsystem and reduces the number of pickup heads required, eliminatespractically all optical problems and enables (because of the fewconnections between scanning device and selector system)'extremely wideseparation between the scanning device on the conveyor line and thecentrally maintained or self-contained cabinet where the electroniccircuitry is disposed.

Furthermore, in the device of the present invention, the photoelectricpickup heads and the case selector logic cabinets may be interchanged.That is, a single logic cabinet may be provided which operateseffectively with a plurality of pickup heads. The relatively inexpensivephotoelectric pickup heads may be disposed in many places along theconveyor system and any one of them may be connected selectively to thelogic cabinet for operating an effective device for removing the cartonfrom the conveyor line. Hence, at many places along the conveyor line aninexpensive detector can be placed without the necessity of providingthe relatively more expensive logic cabinet for each one of the pickupunits.

With the foregoing in mind, one object of the present invention is toprovide a case selector having no more than two photoelectric scanningdevices and which can, nevertheless, select a specific item from amongany number of items passing the selector.

Another object of the present invention is to provide a case selectorwhich may select one or more items from any number of diiferent itemsmoving past the selector, saiili selector utilizing no more than twophotoelectric ce s.

Another object of the present invention is to provide a case selectorwhich will operate at 100% efficiency, regardless of reasonablevariations in conveyor speed, electrical supply, conditions of lightingand the relative condition of the objects to be selected which pass thedetecting portion of the case selector.

Another object of the present invention is to provide a case selectorhaving only two photo electric cells which operate with objects printedwith only x+2 number of marks when the number of cases or cartons fromwhich t(l:1ze )selection is to be made is equal to 2 to the x powerFurther objects will be apparent by reference to the appendedspecification, claims and drawings.

For the purpose of illustrating the invention, there is shown in theaccompanying drawings forms thereof which are at present preferred,although it is to be understood that the various instrumentalities ofwhich the invention consists can be variously arranged and organized andthat the invention is not limited to the precise arrangements andorganization of the instrumentalities as herein shown and described.

In the drawings wherein like reference characters indicate like parts:

FIGURE 1 is a schematic, perspective view of the selector of the presentinvention shown in conjunction with a carton disposed on a conveyorbelt.

FIGURE 2 is a side elevational view of a carton with the pattern ofdetector marks displayed thereon.

FIGURE 3 is an elementary block diagram of the serial input caseselector of the present invention.

FIGURE 4 is a slightly more detailed elementary block diagram similar tothat of FIGURE 3.

FIGURE 5 is a basic block diagram of the selector of the presentinvention.

FIGURE 6 is a more detailed basic block diagram of the selector.

FIGURE 7 is a detailed schematic diagram of the case selector of thepresent invention.

FIGURE 8 is a diagram of a simplified and-circuit.

FIGURE 9 is a diagram of a simplified or-circuit.

FIGURE 10 is a diagram of a storage flip-flop circuit.

FIGURE 11 is a diagram of a counting flip-flop circuit.

FIGURE 12 is a diagram of a one-shot multi-vibrator (pulse stretcher).

FIGURE 13 is a front elevational view of the photoelectric pickup unitor scanner.

FIGURE 14 is a top plan view of the photoelectric pickup unit.

On each carton 10 which passes along the conveyor 11, a plurality ofmarks 12 are placed, in predetermined po sition, in two separatehorizontal lines, as shown in FIG- URES 1 and 2. In one line 13 (the topone in FIGURE 2) a reset marker 14 is placed in line with a series ofcode marks 15 appropriately spaced horizontally from each other aspredetermined for the particular product in the carton. The horizontalposition of the code marks varies from product to product but each markbears specified relation to each other and to the reset mark on eachcase of similar products.

One of the photo electric eyes or photo cells 16 in the pickup unit isvertically aligned with the row of code marks and the second photoelectric cell 17 is vertically aligned with a second horizontal line ofmarks known as clock channel marks. The photo electric eyes arehorizontally off-set from each other, as shown in FIGURE 13, and whenany carton passes the scanning device the first spot to activate a photocell is the reset spot 14 so as completely to clear any informationpreviously c-onveyed to the system. Thereafter, as the carton passes infront of the two photo electric eyes, each eye scans its aligned row ofmarks and conveys suitable electric pulses through appropriate circuitryto the logic cabinet 18 hereinafter described. The system then sends outa pulse or signal which trips an appropriate trigger device 19 forejecting the carton from the conveyor if appropriate information hasbeen conveyed through the circuitry because proper markings on the caseidentify it as one item to be removed from the conveyor.

It is to be noted at this particular time that the only apparatus whichis necessary near the conveyor line for scanning the cartons as theypass is the relatively compact and uncomplicated pickup 20 shown inFIGURES 1, 13 and 14. From this pickup or scanning device appropriatecables 21 may convey the signal to a distant electronic selector unit orlogic cabinet 18 where the receiving, storing, interpreting andtransmission of the signals takes place. The output pulse emanating fromthe logic cabinet is amplified and sent to the trip or ejector 19 forremoving the carton from the conveyor line.

The lower photo cell 17 (and its corresponding input amplifier) iscalled the clock channel. The main function of this clock channel is todirect the information received by the other input channel, the codechannel, into proper locations in the case selector logic circuits shownin FIGURE 7.

Preferably there are two reset marks 14 printed on each carton (FIG. 2).These are in line with the code marks 15 and outside the region of theclock channel marks 22, one before and another after the set of clockmarks. When a carton 10 passes the photoelectric pickup 20 a reset markfirst activates the case selector electronic system to clear or cancelthe previous information. This happens every time the code channel photocell senses a signal from a mark at a time when the clock channel photocell is not simultaneously sensing a similar signal from a clock mark.That is, the system is reset every time the code mark is not alignedwith a clock mark. The photoelectric pickup heads are slightly off-setas shown in FIG- URE 13, so that when both clock and code marks aresimultaneously present, the clock mark is sensed somewhat before thecode mark. The code signal is shortened to a small fraction of theoriginal pulse to prevent a false reset which could be caused by normalirregularities of the printed marks.

The clock channel pickup head 17 scans the clock marks 22 and directsthe code pulses into proper storage or memory locations. After sensingten (or any predetermined number) clock marks, the case selector causesa readout command to be sent to the comparator and-gates of the systemto activate an output mechanism, but only if the information stored inthe storage locations agrees with a pre-selected code pattern.

This readout is accomplished immediately after the clock channel pickuphead senses the tenth clock mark. Irregular defects in the reflectingcarton surface or in the printing within the code mark area may reset orclear the electronic system and thus prevent a readout command.Therefore, the probability of accepting or selecting wrong cartons isvery much smaller than the probability of rejecting or missing correctcartons. A percent performance may be expected if there are no faultycomponents in the case selector circuits and if the cartons and theprinted marks are in reasonably good condition.

It is of particular interest that the marks afiixed to the carton areplaced thereon independently of the edges or corners of the cartons,that a simple scanning mechanism employing only two photo cells is usedto detect and select from among an unlimited number of cartons passingalong the conveyor, that the marks printed on the cartons may be simplerectangular spots and that the system will select from among manycartons with very few spots (the number of cartons and spots beingdetermined by the formula N =2 where N is the number of cartons and thenumber of spots is (x+2)).

In FIGURE 2 the second reset mark is numbered 14a and the second readoutmark 28a. These two marks are printed with the previously describedmarks so that the system will operate with the carton moving in eitherdirection along the conveyor, merely by changing the scanning directionswitch 27 (FIGURE 7).

In a preferred form the case selector selects any five types of cartonsfrom a total of 256 different cartons. However, Without changing thephotoelectric pickup, every additional clock mark 22 on the carton(together with minor additions in the case selector electronic logiccircults) will always double the total number of different cartons thatcan be recognized by the unit. This is accomplished at conveyor speedoperating between 60 ft./min. and 600 ft./min., but preferably atapproximately ft./min.

There are some specific features that make this case selector especiallysuitable for remote control applications. The pickup unit 20 can detectprinted marks on the carton 10 approximately 23 inches away. Therefore,the probability of a faulty behavior and the need for preventingmisaligned cartons is decreased.

Because the pickup unit 20 has only two photo cells, theinter-connections between the case selector logic cabinet and the pickupare very simple. Also, case selectors and pickup units areinterchangeable and can be located as far as several thousand feet fromeach other. There is no sensitivity adjustment to set. If one lamp 23 inthe pickup box burns out, the spare takes over without any interruptionin the operation of the case selector.

Furthermore, because the pickup units are inexpensive and need verylittle maintenance, they can be located in seldom used areas andconnected for use only when necessary.

If so desired, it will be relatively easy to place all case selectorlogic cabinets in a central control room, to build a graphic panel or amodel of the warehouse with plug-in jacks to the stationary pickups, andto connect any case selector anywhere it is needed.

It is also possible to use separate, pre-set counters to determinebeforehand the exact number of each type of cartons required. Thesepre-set counters would suifice as long as only a few case selectorswould be used but to automate an entire warehouse the use of anelectronic digital computer may be desirable so that brands, amounts,locations and loading times could all be punched on tape or on cards andfed in the computer. The computer also could keep records of incomingand outgoing cases and of the total inventory to provide a perpetualinventory control.

The case selector also can easily be modified to eject or count everypassing carton and it can be expanded to separately count every brandproduced.

It is quite possible that local retail organizations which have severalstores and use delivery trucks will often want their purchases loaded inpredetermined assortments which can be unloaded at the local storeswithout additional handling. Such arrangement requires a storage areaeither on the conveyor loop or on the warehouse floor. In this case theuse of present counters or a digital computer becomes very profitable.

It can be seen and appreciated from the foregoing that it is necessaryto feed some information into the selector unit in advance of theoperation of the device.

A group of toggle switches 24 are used to select the desired brands(five rows, eight in each row, one row for each brand). There is also abrand switch 25 and an output delay potentiometer 26 for each row ofswitches 24. Each brand switch determines if the corresponding brandwill be selected. The output delay potentiometers are adjustable fromapproximately 0.3 second to 1 second delay before the case selectortriggers the carton ejecting mechanism. A similar output durationpotentiometer that controls the length of the output is located insidethe cabinet 18.

Also included is a scanning direction switch 27. It is turned to theright if the photoelectric pickup is installed on the right side of theconveyor, when facing to the direction of conveyor movement. Thescanning direction switch should be turned to the left if the pickup isinstalled on the left side of the conveyor.

Although the clock and code marks provide two separate rows of marks,one above another, for practical reasons the code marks may be printedas extensions of the clock marks.

We may consider the printed marks on a carton arranged in two rows,clock and code, even if the printing is not clearly separated. That rowwhich has ten marks (marks 22 plus the two readout marks 28 and 28a) ina continuous regular sequence forms clock marks (this is for casesprinted so as to accommodate travel in either direction). If both resetmarks 14 and 14a and both readout marks 28 and 28a are eliminated, i.e.,one mark from each end of each row of marks, or two marks from both endsof the whole mark pattern, the code area is defined. It covers the areafrom the second to ninth clock mark. This code area can be representedwith an eight digit binary number calling for 0 when the clock mark isnot extended to cover also the code row as a code mark, and calling for1 every time the clock mark is extended to the code row or a code markis present (as at 15). These eight digit binary numbers may be expressedalso as decimal numbers as follows:

Decimal Binary number number When setting the code in each row of eightcode selection switches 24 in the cabinet 18, the switch is down ifthere is no code mark at that particular location, i.e., the binarydigit is 0. If there is a code mark (i.e., the binary digit is l), theswitch is turned up.

Then the output delay potentiometer is adjusted for each brand (row ofcode selection switches) to a suitable value so that the case will beabove the ejector 19 when the ejector is actuated. If the cases areejected too early, the potentiometer is adjusted to increase the outputdelay. If the cases are ejected too late, the potentiometer is adjustedto decrease the output delay.

Without changing the construction or arrangement of the photoelectricdetector systems, but merely by changing the electronic circuitry in theselector systems, a great number of additional items may be scanned andhandled on the conveyor system, because, merely by adding an additionalguide and-circuit, storage circuit and expanding the comparatorand-circuit in the selector system and adding another spot to the casein the code area, the number of units which may be detected will bedouble the amount which previously had been handled by the system.Furthermore, the simple inverter switch 27 on the selector permitsproper handling of the cases regardless of the direction of travel pastthe scanner.

As the case passes in front of the photoelectric eyes, the photoelectriceye in alignment with the clock channel markers scans each mark andemits a square pulse for each mark. If at the same time a code markpulse is emitted, a signal is directed into a proper memory location inthe selector unit. After the case has passed in front of the electriceyes sufficiently far so that all the code mark spots have been scanned,the readout spot 28 passes its photo cell and the case selector thensends out an output pulse (which trips the trigger mechanism forremoving the case from the conveyor line) but only if the informationreceived from the photo cells corresponds to the preset pattern (binarynumber) on the selector switches 24. Because of the integrating networksin both the input channels, the signals passing therethrough are smoothand thus the effect on the operation of irregularities on the cartonsurface and in the printing of the marks is substantially eliminated.

Any one selector system may be set so that a combination of cartons 10may be removed from the system by the same ejector mechanism 19. Atabulating or counting mechanism may be interconnected with the selectorsystem so that when a given number (for example of one type of cartonshave passed through and been ejected, then the case selector willautomatically stop ejecting any more cartons bearing that combination ofmarks and eject only the cartons for which another row of switches 24has been pre-sct, until each of their quotas is filled, and so on, untilthe correct quantity of each of the selected cartons has been removedfrom the conveyor line. With such a device, it is therefore possible tofill a box-car or a trailer truck with the appropriate numbers of anygiven units without attention by an operator other than removing thecases from the end of the ejector mechanism.

CIRCUIT DECRIPTION I. The input stages The photocells 16 and 17 areconnected from the positive side of the logic power supply, to the firstinput amplifier. The input amplifiers consist of three stages. Theoutput of the first stage is transformer-coupled to the second stage.The coupling transformer also inverts the signal so that the secondstage of the input amplifier can be normally cut off. Only the incomingsignals cause this stage to conduct. At the base of the second stagethere is a simple RC low-pass filter or integrating network, thefunction of which is to eliminate high frequency noise from the lowfrequency signal. This decreases the elfects of an uneven reflectingpaper surface and of the small irregularities in the printing of thescanned marks.

The third stage of the input amplifier is nearly a copy of the secondstage but without the filtering network, to pass about 10 c.p.s. signalwithout too much attenuation.

The use of these low frequency, mainly A.C.-coupled, input amplifiersmakes the system less vulnerable to low light level, voltage,temperature, and circuit parameter variations. It also allows widerdistance variations between the photoelectric pickup and the reflectingcarton surface.

' II. D.C.-trigger In order to trigger the logic switching circuits, therise and fall times of the slow input pulses have to be decreasedconsiderably. This is done with D.C.-triggers which are bistablemultivibrators, or flip-flops, which the DC.- coupled output of theinput amplifier forces to swing between two stages when the amplifiedsignal passes through a certain voltage level. The switching time isabout the same as in other switching circuits or about from 0.5 tomicroseconds.

III. Reset This far, both input pulse trains have passed completelyequal amplification and pulse forming stages in clock and code channels.However, the negative clock pulses must be able to completely cover andinhibit the shortened and inverted, originally negative code pulses atthe reset and-gate. Thus, only the code channel pulses with nosimultaneous inhibiting clock pulses are allowed to pass as resetpulses. Therefore, code pulses are shortened in a pulse squeezer.

In order to have an output from the reset and-gate, both inputs mustexit. That is, both inputs must be at the more positive or less negativepotential. Therefore, the originally negative, shortened and invertedcode channel pulses and the negative clock pulses are fed to theand-circuit to get a negative reset pulse from the output of the resetand-gate every time a code channel pulse is present and the clock pulseis not present.

Within the normal scanned code-clock mark pattern, the system willalways be reset in the beginning and at the end of the scanning cycle.Also, because of the /8" horizontal displacement between the staggeredcode and clock photoelectric pickup heads, any vertical line and the endof a carton also will reset the system. Thus the probability ofaccepting wrong cartons is diminished.

The reset pulses switch to zero state all bistable multivibrators, i.e.,counting flip-flops and storage or memory flip-flops. Because of thisrather heavy load, the reset pulse has to be amplified, but withoutphase inversion. This has been done using two inverting amplifierstages.

IV. Code guiding and storage The serial input code pulses have to bestored in proper storage or memory locations for a future comparison,This guiding is accomplished with a binary counter and a set. of eightfive-input guide and-gates. The binary counter is a combination of fourcounting flip-flops. Every flip-flop has two outputs at the oppositestates. One is at the higher voltage level, level 1 (about 1 volt) andanother at the lower voltage level, level 0 (about -6.4 volts). Thevoltage drop across a saturated transistor is about 0.1 volt and thesupply voltage is about 8 volts.

Clock pulses from the DC. trigger switch the first counter flip-flopback and forth. Ten square negative clock pulses are thus divided by twoand reduced to 5 square positive pulses. These trigger the secondcounter flipflop which divides the five pulses to (2+= /2) pulses.Because of the reset pulse after the clock pulse train these 2 /2 pulsesappear as two normal pulses followed by a third pulse with half thewidth of the earlier ones. The third counter flip-flop will divide thetwo normal pulses again into one pulse, but, because only the negativetrailing edge of the pulse triggers the flip-flop, the /2 pulse isignored. The trailing edge of this output pulse of the third countingflip-flop again triggers the last counting flip-flop, which is resetafter about its normal pulse width. Therefore, the output from boththird and fourth counting units is one square pulse. The length of thelatter is A the former.

In the block diagram, the output sides of the counter flip-flops, C -Cand storage or memory flip-flops, M M are marked 1 and s. Output side ris at higher voltage level after reset and output side s is at highervoltage level after one negative input pulse or, in storage units, afterone bit of information, i.e., after a code pulse has been stored in theunit. Each guide-and-circuit is connected to one output side of eachcounting flip-flop via an isolating emitter follower. Thus, each codepulse, that is simultaneously applied at one of the inputs of everyguide-and-circuit gating each storage unit, can pass only through theproper guide-and-gate to the corresponding storage location.

Scanning direction switch 27 allows the installation of thephotoelectric pickup on either side of the conveyor by simply invertingthe order of the storage units.

Thus, finally in the storage units, M M is a perfect copy of the codemarks. This can be understood as an eight digit binary number from00000000=0 to 11111lll=255, and gives the option of selecting any Toselect a specified carton, the operator sets a row of eight codeselection switches, connected to the inputs of a nine-input comparatorand-gate, to couple, via isolating emitter followers, those output sidesof the storage flipfiops that will be at the higher voltage level whenthe photoelectrically scanned binary code number has been stored in theproper storage locations. In short, this means that the row of eightswitches corresponds to an eight digit binary number representing thebinary code on the carton side. If the case selector now finds a casethat has these code marks, all the eight comparator andgate inputs fromthe storage units will be at the higher voltage level.

The ninth input to this comparator and-gate is the positive readoutcommand pulse that will be generated at the last guide-and-gate everytime the binary counter reaches the count ten. Because the readoutcommand pulse has to be positive, the originally negativeoutput from aguide and-gate is passed through a basically A.C. coupled invertingamplifier. If the proper code combination is now in the storage units,the comparator andgate will pass the readout command pulse which willnow be the output of the logic system. This is a negative pulse.

VI. The output stages The comparator and-gate negative output pulse isthe output of the case selector basic logic circuit. How- 9 ever, thispulse must be modified to drive an output mechanism.

First this negative pulse is passed to a pulse stretcher which acts asan output delay. This can be adjusted from 0.3 to 1 second. The outputof this pulse stretcher is connected to a two stage emitter followerpower amplifier (which may also control an indicator light to show if acertain brand is selected.)

The trailing negative edge of the output delay pulse triggers the lastpulse stretcher which now controls the duration of the output from thecase selector. The output of this pulse stretcher is again connected toa twostage emitter follower power amplifier. This drives the outputrelay or output switching reactor that finally controls the cartonejecting mechanism of the case selector.

By way of illustration, it was desired to preset the case selector toselect any five brands from the total of 256 brands and hence five rowsof code selection switches and five corresponding comparator and-gatesare used in parallel, as shown. Their outputs after output delay pulsestretchers and power amplifiers are combined in an or-circuit to triggerthe common output pulse stretcher. This arrangement provides only onefinal output.

Of course it is possible to keep all five outputs also separated. If theindicator lamps are replaced by mercury wetted contact relays, undelayedoutputs from each five channels and a single delayed common output isprovided. 1f five individual delayed outputs are required, fiveadditional output pulse stretcher-power amplifier combinations have tobe added, one after each output delay pulse-stretcher or correspondingpower amplifier. By changing the location of the or-circuit one pulsestretcher may be eliminated. If a common delayed output is notnecessary, the or-circuit and the following power amplifier also can beeliminated.

If, an output for every code-marked carton is desired, it can beaccomplished simply by first disconnecting the output of anycomparat-or-and-gate from the input of the following output delay pulsestretcher. Then the original negative readout command pulse before theinverting amplifier is connected, via a diode passing only negativepulses, to the input of the above output delay pulse stretcher. If nooutput delay for this operation is necessary, the common output pulsestretcher also can be used.

It might also be desired to use preset counters to determine how manycartons of each brand are wanted. This is done by connecting the outputof every output delay power amplifier through a set of normally closedcontacts or" a preset counter output relay. Thus, when the desirednumber of cartons has been ejected, this preset counter output relayopens its contacts and prevents all further actuations of the finaloutput stages of the case selector from this brand selection channel.

Thus, all five brand selection channels operate individually. If thecontacts of the preset counter output relay are between the emitter ofan output delay power amplifier power transistor and the correspondingbrand switch 25 the preset counter input is condenser-coupled to theemitter of the power transistor. The preset counter must be set tooperate only from negative pulses. The case selector and the presetcounter have a common ground connection.

Reference has been made to three specific portions of the circuitrywhich will be more fully described.

(1) BISTABLE MULTIVIBRATORS (FLIP-FLOPS) When no triggering pulses areapplied, one side, i.e. one

a condenser and a series diode.

amplifier transistor is always conducting, often completely saturated,and another side is cut oif. Consider the conducting side. Because ofthe flowing current, there is a very large voltage drop across thecollector resistor and a very small, usually about 0.1 volt, voltagedrop across the transistor between collector and emitter. Thisconduction state is caused by a heavy forward bias current to the baseof the transistor provided through a forward bias cross-couplingresistor from the collector of the other nonconducting transistor.Because very little current is fiowing, the collector of thenon-conducting transistor is nearly at the power supply potential, i.e.very near the positive voltage. The bias current to the base of thenon-conducting transistor is also provided through a forward biascrosscoupling resistor from the collector of the conducting transistor.As mentioned earlier, the collector of the conducting transistor is verynearly at the emitter potential. However, to insure safe operation and aclear cut off state even at higher temperatures when the gain andleakage of the transistors increase, the bases of both flipfloptransistors are also, via reverse bias resistors, connected to thenegative power supply terminal (with NPN transistors, or to the positiveterminal if PNP transistors are used).

In the storage or memory units, the basic flip-flops are triggered to 0or 1 states with negative pulses at the base of either transistor.However, the counter units must be able to alternate their states fromthe same input pulses. This is afforded by connecting the input couplingcondenser via diodes simultaneously to the bases of both flip-floptransistors. The negative triggering pulses try to cut off bothtransistors. Nothing happens to that transistor which is not conductingbut the conducting transistor will be cut oif. It will change its state,and hence switches both sides of the flip-flop to the opposite states ofconduction and cut off. The output of a counting flip-flop directlyoperates the next counting flip-flop, and all are reset to zero state bya reset pulse. The size of the reset coupling condensers has to berelatively large because the reset pulse has to last long enough tocounteract the mutual switching effects of the counter flip-flops.

(2) ONE-SHOT MULTIVIBRATOR (PULSE SQUEEZER AND PULSE STRETCHER) Thereason for calling one one-shot multivibrator a pulse stretcher andanother one-shot multivibrator a pulse squeezer is that the output pulseof the former is usually longer and the output pulse of the latter isshorter than the input pulse.

One-shot multivibrators can be considered as modified bistablemultivibrators and are used to form on standardize pulses, especially tochange the duration of the pulses. Preferably the base of the firsttransistor on the input side of the one-shot multivibrator is forwardbiased. This saturates the first transistor. A forward biascross-coupling resistor connects the collector of the first transistorto the base of the second transistor, exactly as in the bistablemultivibrator. This forces the second transistor to switch together withthe first transistor, but in the opposite phase. However, the otherforward bias cross-conpling resistor is omitted and only a timercondenser is connected between the collector of the second transistorand the base of the first transistor.

When a negative triggering pulse at the base of the first transistorcuts it off, the second transistor switches into the conducting state.This suddenly swings the potential of the timer condenser down. The baseof the first transistor stays reverse biased until the charge of thistimer condenser has reached a new equilibrium. Then the normal constantforward bias of the first transistor takes over and switches again thefirst transistor into the conducting state and the second transistorinto the cut off state.

The input to this one-shot multivibrator is coupled via This diodepasses only negative pulses which may be caused also by negative goingvoltage steps. Thus the input pulse will normally only trigger theone-shot multivibrator. The duration of the square pulse is determinedby the electrical charge stored in the timer condenser and by the totalresistance of all parallel leakage paths, or its time constant, RC. Thepulse length can be controlled by changing either the capacitance of thetimer condenser or, less expensively, the resistance of a leakage path.

The only basic difference between a pulse stretcher and a pulse squeezeris the difference in the value of the time constant, RC, determined asthe product of the timer condenser capacitance, C, and the totalparallel leakage resistance, R.

CIRCUITS (AND-CIRCUITS ND ORCIRCUITS) And-Circuit or And-Gate is ashorthand notation for a bistable circuit with states and l, which willhave an output, usually designated as 1 state, when, and only when, allinput signals exist simultaneously. If even one input does not exist,that is, its level is 0, there will be no output.

The Or-Circuit or Or-Gate will have an output 1 every time when one ormore inputs exist, that is, have the level 1.

FIGURE 8 shows a simple And-Circuit. There the output level isdetermined by the lowest input level. FIGURE 9 shows an Or-Circuit. Inthis case, the highest input level determines the output level. Boththese circuits assume that a more positive signal level is called 1state. If the polarities of the inputs and output are interchanged, thefunctions of the circuits are interchanged.

In the present invention there has been added an inverting amplifierstage to the And-Circuit.

This type of And-Circuit does not require that all inputs are connected.Some diodes may be just floating. Therefore, if the number of inputdiodes provided is large enough only one type of And-Circuit would benecessary.

The use of two slightly different And-Circuits in the case selector iscaused by the difference of the triggering input pulse. The in-input,comparator-and-gates include a series diode and parallel condensercombination to limit the positive overshoot at the output of theinverting amplifier.

Maintenance of the case selector is relatively simple because etchedcircuit plug-in boards are used which enable the operator to locate andseparate parts of the circuit. Also, the reliability of the system isbetter than the reliability of normal vacuum tube circuits because thereare no vacuum tubes in the case selector. Instead, germanium transistorsand silicon diodes are used as active circuit elements.

It is to be understood however that the present invention may beembodied in other specific forms without departing from the spirit oressential attributes hereof, and it is therefore desired that thepresent embodiments be considered in all respects as illustrative andtherefore not restricted, reference being had to the appended claimsrather than to the foregoing description to indicate the scope of theinvention.

Having described my invention what I claim as new and desire to protectby Letters Patent are the following:

1. An object identification system comprising a series of code markingsand a related series of clock markings on the object to be identified, afirst detector device for serially sensing said clock markings, a seconddetector device for serially sensing said code markings, a logic systemcoupled to said detector devices and including means for storing inbinary number form the series of simultaneous occurrences andnon-occurrences of clock and code markings sensed by said first andsecond detector devices, and a presettable read-out system responding tothe binary number condition of said storage means.

2. An object identification system as set forth in claim LOGIC U A 1including means triggering said read-out system responsive to said firstdetector device sensing a predetermined number of clock markings.

3. An object identification system as defined in claim 1 including meansfor resetting the logic system in response to said second detectordevice sensing a code marking when said first detector device is notsensing a clock mark- 4. In apparatus for distinguishing betweendiffering marking sets each comprising a plurality of clock markings anda plurality of code markings, the combination of first detector meansfor serially scanning said clock markings and producing a series ofelectrical pulses corresponding to said clock markings, second detectormeans for serially scanning said clock markings and producing a seriesof electrical pulses corresponding to said clock markings, a countingcircuit triggered by said clock pulses for sequentially directing clockpulses and simultaneously occurring code pulses to a logic systemadapted to record in binary number form the pattern of simultaneousoccurrence and non-occurrence of individual clock and code pulses and apresettable read-out circuit adapted to read the binary number conditionof said logic system and produce a usable output signal in response toreading a binary number condition for which it has been set.

5. Apparatus for selectively identifying an object from among aplurality of objects, said objects bearing indicia in the form of aseries of code markings and a related series of clock markings, saidapparatus comprising detector means for scanning the indicia on saidobjects and providing a series of code signals corresponding to codemarkings observed and providing a series of clock signals correspondingto the clock markings observed, counter means and a plurality of guideunits, said counter means receiving a series of clock signals from saiddetector means and selectively and serially conditioning individualguide units, means for applying code signals from said detector means tosaid guide units, a series of storage units, there being a differentstorage unit connected to each of said guide units, each of said guideunits being adapted to permit a code signal applied thereto to pass toits storage unit when conditioned by said counter means and to block thepassage of a code signal when not conditioned by said counter means,each storage unit being capable of assuming a set condition from a resetcondition upon receiving a code signal from its guide unit, whereby theseries of storage units is capable of storing in binary number form theseries of simultaneous occurrences and nonoccurrences of code signalsand clock signals provided by said detector means, a read out circuitadapted to be set to respond to a particular binary number condition ofsaid series of storage units, and a read out command circuit connectingsaid counter means with said read out circuit for triggering said readout circuit in response to said counter means receiving a predeterminednumber of clock signals.

6. The apparatus as set forth in claim 5 including means for resettingsaid storage units in response to a code signal produced in the absenceof a clock signal by said detector means.

7. Apparatus for selectively identifying a plurality of differentobjects from among a larger plurality of objects, said objects bearingindicia in the form of a series of code markings and a related series ofclock markings, said apparatus comprising detector means for scanningthe indicia on said objects and providing a series of code signalscorresponding to code markings observed and providing a series of clocksignals corresponding to the clock markings observed, counter means anda plurality of guide units, said counter means receiving a series ofclock signals from said detector means and selectively and seriallyconditioning individual guide units, means for applying code signalsfrom said detector means to said guide units, a series of storage units,there being a different storage unit connected to each of said guideunits, each of said guide units being adapted to permit a code signalapplied thereto to pass to its storage unit when conditioned by saidcounter means and to block the passage of a code signal when notconditioned by said counter means, each storage unit being capable ofassuming a set condition from a reset condition upon receiving a codesignal from its guide unit, whereby the series of storage units iscapable of storing in binary number form the series of simultaneousoccurrences and nonoccurrences of code signals and clock signalsprovided by said detector means, a plurality of read out circuits eachbeing adapted to be set to respond to a different binary numbercondition of said series of storage units, and a read out commandcircuit connecting said counter means with said read out circuits for 8.The apparatus set forth in claim 7 including means for resetting saidstorage units in response to a code signal produced in the absence of aclock signal by said detector means.

References Cited by the Examiner MALCOLM A. MORRISON, Primary Examiner.

triggering said read out circuits in response to said counter 15 ANGEL,Examine!- means receiving a predetermined number of clock signals.

1. AN OBJECT IDENTIFICATION SYSTEM COMPRISING A SERIES OF CODE MARKINGSAND A RELATED SERIES OF CLOCK MARKINGS ON THE OBJECT TO BE IDENTIFIED, AFIRST DETECTOR DEVICE FOR SERIALLY SENSING SAID CLOCK MARKINGS, A SECONDDETECTOR DEVICE FOR SERIALLY SENSING SAID CODE MARKINGS, A LOGIC SYSTEMCOUPLED TO SAID DETECTOR DEVICES AND INCLUDING MEANS FOR STORING INBINARY NUMBER FORM THE SERIES OF SIMULTANEOUS OCCURRENCES ANDNON-OCCURRENCES OF CLOCK AND CODE MARKINGS SENSED BY SAID FIRST ANDSECOND DETECTOR DEVICES, AND A PRESETTABLE READ-OUT SYSTEM RESPONDING TOTHE BINARY NUMBER CONDITION OF SAID STORAGE MEANS.